"Obviously," "clearly," "inarguably": my dissertation adviser (Jane Thrailkill, a fantastic writer and editor) calls these types of words "wallpaper words"--words that writers use to try to paper over a crack in argumentation or logic. When you find yourself using these terms in your writing, that should be a yellow flag: there's something you're leaving out or something that you don't want to explain or examine in that spot. Go ahead and explain whatever it is you're leaving out--your piece will be stronger for it.